Methods for limiting a switch-on current in an electrical system, in particular a high-voltage network, with which pre-charging is undertaken via a pre-charging resistor during a switch-on operation so that a switch-on current which flows through a battery and a connected load is reduced, are known from the prior art. In such a system, the pre-charging resistor is short-circuited and therefore deactivated when the system voltage has adapted itself to the battery voltage. However, if such pre-charging takes place several times within a very short time, the pre-charging resistor can overheat.
Such overheating of the pre-charging resistor should particularly be avoided in battery systems on which very high demands with regard to reliability are placed, for example in systems such as those used in hybrid and electric vehicles. The background for the high demands is that, in such systems, a failure of the battery can lead to a failure of the whole system. For example, in an electric vehicle, a failure of the traction battery leads to a so-called “stranded vehicle”. Likewise, a failure of the battery can lead to a safety-related problem, for example if the battery can no longer be isolated from the on-board vehicle network.